This invention relates to laminated materials, suitable for use as materials for protective clothing, to guard against hazardous material (hazmat) exposure. One hazard that a hazmat cleanup specialist is confronted with is the exposure to and subsequent skin contact with toxic chemicals or materials.
Various protective clothings are known in the art to prevent skin contact with toxic agents. Some of this clothing is made out of laminated materials such as the material described in Nuwayser, U.S Pat. No. 4,214,321 and Athey, Jr., U.S. Pat. No. 4,588,646. The purpose of using a laminate material is to create a composition that contains the most desirable properties of the individual layers. For example, a material may be a composite of a chemically resistive barrier; to prohibit the passage of a chemical through the material and, a substrate material that strengthens the chemical resistive barrier so that the composite can be used to make clothing garments.
Various laminates have been created to provide protection from chemicals having a variety of properties. For example, the Mine Safety Appliances Company (MSA) of Pittsburgh, Pennsylvania sells two different protective suits. The first suit is comprised of a three-layer material of Viton.RTM. on a nylon substrate on neoprene. This suit is used for cleanups of spills such as, for example, benzene or gasoline. The second type of suit manufactured by MSA is comprised of a three-layer material of butyl on polyester on neoprene. This laminate composition is effective for use in cleaning spills such as acetone or chlorine.
Other types of laminates known in the art are comprised of layers that are individually laminated or coated with a chemical resistive polymer material. Examples of such coated laminates are Snyder, U.S. Pat. No. 3,547,765, Effenberger et al. U.S. Pat. No. 4,610,918 and the abandoned application of Effenberger et al., Ser. No. 599,766, filed Apr. 13, 1984. In each of these disclosures, a substrate material is coated with a copolymer that adheres to a substrate. The process of coating the substrate necessarily requires numerous production steps resulting in high production costs. It is also difficult to maintain quality in producing the materials in that the coated material is susceptible to the formation of pin holes and breakthroughs in the polymer coating. Pin hole formation can result in leaks and the subsequent breakthrough of the laminate material causing possible skin exposure to the toxic agents. The Snyder patent and the Effenberger patent discloses the use of polytetrafluoroethylene (PTFE) either as a substrate material or a coating material. Polytetrafluoroethylene, sold under the E. I. DuPont de Nemours trademark Teflon.RTM. , is a well known coating material used to reduce friction on household items and in industrial applications. However, although Teflon has exhibited good resistance to chemical degradation, it displays poor permeation resistance qualities.
The process of forming Teflon into sheets is known as skiving. Teflon is particularly effective against chemical permeation when it is formed from skived rolls. Skived Teflon sheets are virtually pin hole free and accordingly, chemical permeation normally occurs only as the Teflon layer breaks down from cracking that develops from abrasions of the layer. Teflon coated fabrics such as those disclosed in the Snyder and Effenberger references do not possess the same permeation resistive qualities as the solid skived Teflon layers since Teflon coated materials often inherently contain pin holes and cracks. Accordingly, it would be desirable to provide a laminate material that has a chemical barrier comprised of at least one layer of skived Teflon.